class Solution
{
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid)
    {
        int m = obstacleGrid.size(), n = obstacleGrid[0].size();
        vector<vector<int>> dp(m + 1, vector<int>(n + 1));
        dp[0][1] = 1;
        for (int i = 1; i <= m; i++)
            for (int j = 1; j <= n; j++)
                if (obstacleGrid[i - 1][j - 1] == 0)
                    dp[i][j] = dp[i][j - 1] + dp[i - 1][j];

        return dp[m][n];
    }
};